LCD display modules comprise a display panel and a backlight, in which a side of the display panel is attached to a light-emitting side of the backlight. The display panel comprises a plurality of pixel elements, usually arranged in a matrix formation, wherein each pixel element may be controlled individually to be in a transparent state or an opaque state. By selectively controlling each pixel, an (moving) image may be created. The backlight is arranged for producing light that is allowed to pass through the transparent pixels of the display panel and is blocked by the opaque pixels to create an illuminated image on the side of the display panel not attached to the backlight.
In such modules for LCD display from the prior art the display panel is attached to the backlight by a double sided adhesive (DSA or rim sheet). The rim sheet is attached on one side to a circumferential area on the side of the display panel and on the other side to a corresponding circumferential area on the side of the backlight. Typically the rim sheet is shaped as a frame coinciding with the outer edges of the display panel or backlight. The shape of the frame is for example rectangular. The circumferential areas of the display panel and the backlight have no further purpose than to provide on one part (the display panel) a surface for fixation to the other part (the backlight).
A variety of electronic devices comprise a display module. Such electronic devices may be telecommunication devices such as smartphones, PDA's, gaming devices, audio/video player devices, etc. However, in the design of electronic devices that comprise a display module a trend is observed that the so-called Gakabuchi's of panels, i.e., the circumferential area of the panel is getting smaller and smaller. This is driven by the desire for smaller and thinner electronic devices, while at the same time the relative area for the display within the electronic device increases.
The reduction of thickness and of available circumferential area has an adverse effect on the fixation of LCD panel and backlight. Due to the desired reduction of the thickness of the LCD module, also a reduction of the thickness of the rim sheet will be required. Moreover, since the circumferential area is to be reduced, the width of the rim sheet also needs to be reduced. The reduction of thickness and width of the rim sheet causes a reduction of adhesion strength of the rim sheet.
As a result of the reduction of adhesion strength a display panel may become detached from the backlight before assembly into an electronic device.
A further problem is that no adequate tool is available for cutting or punching such narrow-width and thin rim sheet frame as demanded by modern designs as described above.